The present invention relates generally to the treatment of biodegradable waste products and, more particularly, to a wastewater treatment system utilizing aerobic microbial growth on fixed media for biological oxidation of waste products that can be retrofitted into existing septic tanks.
At the present time, many single-family homes and small multi-family homes that are not connected to a central sewer system employ a septic tank system for the disposal of biodegradable wastes, particularly sewage. These tanks are generally of very low efficiency in processing these wastes, and, as a result, often tend to pollute the environment. Accordingly, there is a need for a high-efficiency system for the treatment of biodegradable waste products which can be used in conjunction with, and to upgrade, existing septic tank systems.
There have been many systems introduced to address the above-discussed problems associated with conventional anaerobic septic tank systems. The most commonly used systems replace the septic system with an aerobic wastewater treatment system. Examples of such systems are disclosed in U.S. Pat. Nos. 3,966,599, 3,966,608 and 3,972,965, which patents are assigned to the same assignee as the present invention, and the disclosures of which are incorporated herein by reference. These systems generally comprise a settling tank having an inlet communicating with an upper portion thereof and a reactor chamber having an inlet communicating with the settling tank. A column of fixed high surface area-to-volume ratio media is disposed within the reactor chamber. Aeration means are provided in the reactor chamber for introducing air into the liquor containing biodegradable wastes and means for delivering and recirculating the liquor through the fixed media. The treated effluent liquor is withdrawn from the reactor chamber. The replacement of septic tank systems with these high efficiency aerobic wastewater treatment systems has solved most of the environmental problems associated with septic tank systems.
However, these aerobic wastewater treatment systems, when used to replace or supplement an existing septic tank system, typically require the use of excavation equipment and hoisting systems, which is costly and causes damage to a yard. This problem is recognized in U.S. Pat. No. 5,162,083, wherein an apparatus is disclosed for converting a standard anaerobic septic tank system into an aerobic wastewater treatment system. The apparatus contemplates the removal and modification or replacement of the septic tank lid. An air diffuser assembly and a clarifier insert are positioned within the septic tank. The clarifier insert is disclosed as being made from fiberglass or A-36 carbon steel. The clarifier insert does not contain media. The installation of the apparatus requires the removal of the earth above lid and the removal of the lid in order to install the component parts of the apparatus in the septic tank.
There is a need for a high efficiency aerobic wastewater treatment system that can be installed through the relatively small opening in the top of an existing septic tank and which contains media through which the waste liquor is recirculated.
In accordance with the present invention, an apparatus is provided for converting a typical anaerobic septic tank system into an efficient aerobic. treatment system for treatment of liquor containing biodegradable wastes. The invention includes a collapsible reactor module that is capable of being folded to pass through the opening in the cover of a septic tank and unfolded to provide a reactor chamber supported within the septic tank. The corner sections of the reactor module are corrugated to facilitate the folding and unfolding thereof. The reactor chamber is supported from the cover of the septic tank by a plurality of strips that are secured to the cover of the septic tank.
A draft tube extends centrally through the reactor module through which liquor to the treated is recirculated. Media is positioned within the reactor module in surrounding relationship with the draft tube through which the liquor recirculates.
An aerator assists in the recirculation of the liquor and introduces air into the recirculating liquor. The aerator may include an air line extending through the draft tube such that an open end is located adjacent a lower portion of the reactor module and the other end is in communication with a blower device located outside of the septic tank.
The instant invention and the operation thereof will now be described with particular reference to the accompanying drawings which form a part of this specification wherein like reference characters designate the corresponding parts in the several views.